Noise

1-1      Please explain in detail whether the proposed facility will fully comply with the Town’s noise ordinance.

1-2      Please explain in detail whether and to what extent the facility will seek relief from the Town’s noise ordinance limitations.

1-3       Please explain in detail the difference in expected noise levels between start up and shut down operations and normal operations.

1-4       Please explain in detail the expected noise level that will be generated during steam releases.

1-5       Please explain in detail the expected noise levels that will be generated during (a) normal operations, (b) startup operations, (c) normal shut down operations, (d) steam releases, and (e) emergency shut down operations.  Please provide details for both natural gas operations and fuel oil operations.  Please identify the models used to project the noise levels during each such phase of operations (a) through (e).

1-6       Please explain in detail all noise suppression/mitigation efforts that are being proposed by the facility.

1-7       Please explain in detail the additional noise to be generated by the proposed on site compressor.

1-8       Please explain whether the facility will be able to maintain compliance with the Town’s overall 43 dBA noise limit (applicable at the nearest houses) during all non-emergency operating conditions, including most importantly, normal startups and shut downs.

1-9       Please explain why is there no mention of the potential noise impact during normal startup and shut down in the noise section of the permit application.

1-10     Does Invenergy, or its parent or related company, operate another combined cycle plant that uses an air cooled condenser (ACC)?  If so, please identify the plant and the noise mitigation installations in each such plant.

1-11     Do you agree that the noise generated during the steam turbine bypass phase of startup—when high pressure steam is injected directly into the vacuum of the main duct of the ACC is going to be extremely loud if no mitigation efforts are made?  Please provide details.

1-12     Please detail all steps Invenergy plans to take, such as for example, with the bypass valve, hogging air injector and drain vent, to maintain the sound level below 43 dBA during normal startups

1-13     Please provide details regarding the expected noise to be generated by traffic (truck and other vehicles) during construction and routine operations.

1-14     Please identify the details of the expected noise to be generated during construction operations.

2-1       Table 1 on Page 7 of Appendix A (“Transient Operation Noise Level Evaluation for the Clear River Energy Center”, Michael Theriault Acoustics, Inc., March 2016) contains the expected near field sound pressure levels at various points along the air cooled condenser (ACC) duct during steam turbine bypass.  Could you please explain the source or derivation of the values specifically associated with the following sources:

  1. ACC Main Horizontal Ducts
  2. ACC Riser Ducts
  3. ACC Finger Ducts     
  4. HRH Steam Bypass Ducts
  5. LP Steam Bypass Ducts

2-2       Will the facility use a steam jet air ejector or vacuum pumps for condenser vacuum hogging during start-up?

2-3       Will the steam turbine drains tank discharge directly into the vacuum of the ACC duct to preserve demineralized water or will it vent to atmosphere?

2-4       Will either or both of the hot reheat (HRH) and low pressure (LP) bypasses join the ACC duct inside the turbine building or outside?

2-5       What is the anticipated sound power level of each ACC fan?  Is the make and model known at this point?  If so, please identify the make and model.

2-6       The noise modeling analysis suggests that the best sound level that can be realized at Receptor M1 during a normal start-up is 46 dBA.  Does that mean that Invenergy believes that compliance with the overall 43 dBA Town Ordinance (neglecting the octave band component) cannot be achieved?

4-30     Is there available sound generating equipment or a machine that can demonstrate the 45 decibel sound level?

6-8       Please explain in detail how the adjacent gas compression station noise levels will impact the noise levels of the power plant (what will the projected combined noise levels be)?